Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: lgr on February 17, 2010, 10:56:20 PM

Title: electrical interference
Post by: lgr on February 17, 2010, 10:56:20 PM
Hi everyone this is my first attempt at converting a router to Mach 3 and I've just hit a wall. Any help or suggestions would be appreciated.

It's being installed on a Camtech router formerly running on wincnc it has a 5.5hp perske spindle driven by a yaskawa gpd315/v7 inverter. The breakout board has been replaced with a C11G v7.1 from cnc4PC.

I had a problem with the software not recognizing the homing switches for the y and z axis and the on screen led indicators for the limit switches would flicker occasionally. After I read some posts about similar problems on this forum I grounded one end of all of the shielded wires to a single point. A friend of mine has a HASS mill and he was told by the HASS technician to install a ground rod on the other side of the wall behind the electrical box that the machine connects to and ground the box to it. So I did this as well.
The new problems are when I toggle the spindle on using either the F5 or the screen button the spindle turns about a half a revolution and kicks out the screen reset. I'm just using the on-board relay to start and stop the spindle, no speed control yet. The other on-board relay is connected to the flood coolant button and I use that to start a dust collector and it works fine.
The reset also randomly kicks out every minute or so when the machine is just sitting there with the steppers in hold mode.

Things I've tried;
Adjust the debounce interval to 6000 and the index debounce to 900. This has improved the reset problem but the spindle will still randomly cause a screen button reset after 10-15 minutes of run time.

I ran a 6 gauge ground wire directly from the wire shield common ground in the panel to the 10 ft copper coated ground rod outside, no plugs no connectors. The earth is a bit sandy and dry so I'm not sure how good the ground is. This is in addition to the 12 gauge ground in the machine power cord.

Other Tidbits;
The power supply to the machine is 240V 1 ph. I have a 120V plug on the machine to run the panel and computer, this plug is a GFI with a surge protector plugged into it.

The power wire for the spindle is shielded  and the shield grounded on one end. I run a separate shielded wire for the spindle ground.

The first 5 ft of spindle power and ground wire run under the metal electronics cabinet, thought this might have been an issue but the spindle started and stopped o/k. For even more shielding I ran this wire through  a 1/2”  metal conduit. Now when I try to start the spindle it kicks out the GFI. If I run a separate extension cord from another outlet to power the panel and computer I can start the spindle without incident, except it still kicks off the Mach 3 reset after 10 or 15 minutes.

Until I grounded the shield on my incoming phone/DSL internet wire the spindle would kick off the internet any time I would run it. The  phone/DSL internet wire doesn't come any closer than 30 ft to the spindle.
Title: Re: electrical interference
Post by: lakeguy2 on February 18, 2010, 12:34:33 AM
   Just a stab in the dark........sounds like some strong EMF. If your grounding is truely grounded, the noise could feeding through both phases, not just the ground. I would try to isolate the control power as much as you can from the motor.  sounds like your gfi is in line off of one phase. which is probly not even fused? you could install a in line 110v filter immediately before electronics. also you probly need to install some .1uf capacitors on your inputs. they are I believe ceramic or mylar non-polarity. there are different ways to install them some say on the switch side, some say board side parallel, some say from switch to ground? most all say this will get rid of most if not all noise. maybe others could shed some light on the proper way to hook them up? I would think parallel on  board side would be correct but dont know? 
Title: Re: electrical interference
Post by: lakeguy2 on February 18, 2010, 12:50:33 AM
   Forgot you may also  use resistors to pull inputs high or low. depending on your board and switch type. opto or mechanical? I think if you are using simple mechanical switch, a 1k resistor pulled high or low in combination with a .1uf cap will fix your noise problem.
Just my stab at it though? any criticism or other solutions welcome!
Title: Re: electrical interference
Post by: lgr on February 19, 2010, 10:13:54 AM
Thanks for the info Steve, I contacted the Yaskawa inverter tech rep and he was great. He helped me change some programming in the drive although it didn't fix the problem he also had a part number for the recommended RFI filter for the input side of the drive. Your right the 120v outlet hasn't been fused separately yet, it's on the list once everything else is sorted out. It is after the main power switch though and I never leave it on except when I'm there. I'll check with the board manufacturer and see what they recommend for resistors and capacitors, if that doesn't work I may be back to bother you again.
Title: Re: electrical interference
Post by: zarzul on February 19, 2010, 12:59:18 PM
You should get a message  in the STATUS:  message line telling you what caused the reset to go off.
something like External Estop Requested, or Limit Switch Triggered

Then you can do things like disable your -- & ++ limits one at a time and determine which one is tripping you off.
Title: Re: electrical interference
Post by: lgr on February 19, 2010, 02:49:18 PM
Thanks Zarzul thats a good trouble shooting tip. It showed up as "limit switch triggered" so i disabled one switch at a time and it kept doing it until they were all disabled. I took the backs off the switches for the first time and the two connectors have a resistor?? with k5k on one side and 104 on the other side jumping the two terminals is this good or bad for the mach and c11g board? I also discovered that the "shielded" switch wiring has a plug about 12" from the end of the wire that the shield conductor doesn't jump so that last foot of wire that sits right next to two stepper motors really has no shielding. I think I will just replace the wire and wire directly from the board to the switches and see what happens.